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Wheel System, Traction
182
Service Manual – SC6500
™
Wheel System, Traction
Functional Description
A single front wheel provides both traction drive and steering. The major components of the drive wheel
system are the drive pedal, wheel drive controller and drive wheel motor assembly. The drive wheel is
mounted to a front spindle which carries the vehicle load and provides a steering pivot. The gearbox is
driven by a brush-less three phase AC motor. The drive wheel controller directly operates the drive motor
based on input requests from the drive pedal sensor (potentiometer) which is mounted on the side of the
drive pedal. If you push the pedal forward, the machine will move forward. If you push it farther forward,
the machine will increase speed. If you push the pedal backward, the machine will move in reverse. The
drive pedal is spring loaded in the center or “neutral” position.
Drive Pedal
The drive pedal is spring loaded in the neutral position. The drive pedal position sensor is a potentiometer
mounted on the side of the pedal that tracks the pedal position. The sensor is pre-adjusted and comes with
the pedal assembly.
Wheel Drive Controller
The wheel drive controller is a self contained sealed unit. It controls when and how the current flows to the
stator windings to rotate the motor based primarily on the drive pedal sensor input, but it also monitors
rotational speed sensors and a temperature sensor inside the motor.
The wheel drive controller has 5 bolt-on connector lugs. Two for battery positive and negative supply and
three for the motor U, V and W circuits. There is also a single “low current” connector.
Drive Wheel Motor Assembly
The drive wheel motor assembly consists of a wheel, gear box and a brush-less three phase AC motor. The
motor drives the wheel through a gearbox. The wheel drive motor can change rotation direction to propel
the machine both forward and backward.
Figure 1: Drive Pedal with
sensor (Potentiometer)
Figure 2: Wheel Drive
Controller
Figure 3: Drive Motor Assembly
Potentiometer